1. Field of the Invention
The present invention relates to a technique that predicts traffic states.
2. Description of the Related Art
Japanese Patent Application Laid-Open Publication No. 2006-171835 describes a technique that obtains the level of congestion on a link. For example, a travel speed is obtained from the travel time and link length of a link, and the level of congestion corresponding to the obtained travel speed is taken as the level of congestion on the link.
However, even for one link, the traffic state is not necessarily the same from its start point to its end point. For example, if an intersection or a slope exists at some point on the link, congestion may occur starting from that point. That is, sections in the one link may differ in their congestion state. With the conventional technique, the detailed congestion states (sections classified according to their level of congestion) of a link cannot be obtained even if the travel time of the link is obtained.